I was on oxycodone after surgery for 5 days, and I took senna (a stool softener) just like my surgeon told me to. Oh my god the constipation was insane. Like, I had to poop and just nothing would come out. I could not move my bowels. I ended up taking Miralax twice a day for 4 days and that solved the problem...a little too well. It went from completely stopped up to faucet anus with no stop in between.